Solvent composition



Patented May 2, 1944 SOLVENT COMPOSITION William J. Backoi! and NormanD.

cago, 111., assignors to The a corporation of Ohio Chicago, 111.,

Williams, oin- Pure Oil Company,

No Drawing. Application March-'14, 1941,

. Serial No. 383,352

11 Claims.

This invention relates to new compositions of matter and to methods ofpreparing and using the same. While these compositions may have a widevariety of uses, they are particularly effective as solvents for theremoval of carbon and gum deposits from internal combustion englnes.

It is well known that in the course of man-- ually handling hydroxybenzene ring compounds, such as phenol and cresol, there is a relativelyhigh degree of hazard involved due to the fact that such compounds causesevere irritation to human skin with which they come in contact, suchas, for example, the skin covering the hands, arms and face. Thisescharotic or irritant property of the hydroxy benzenes seriouslyinterferes with the use of such compounds for many applications. Thishas been found to be particularly true when using such materials assolvents or as components of solvents used for the removal of carbon andgum deposits from internal combustion engines. It is frequentlydesirable to apply such solvents to the engines by injecting the solventinto the affected zones with a pressure atomizer.

A preferred method of injecting the solvent is to remove the air cleanerfrom the carburetor and while the engine is running, slightly fasterthan idling, a suitable portion of the composition is injected into thethroat of the carburetor. The ignition is then turned off, the sparkplugs removed and additional composition injected into the enginethrough the spark plug holes, using the pressure atomizer. The sparkplugs are replaced, the engine allowed to stand for about fifteenminutes, then run for a short period of time with the throttle partiallyopened and then accelerated intermittently until the exhaust issubstantially devoid of smoke.

Under such conditions'of use it is almost impossible to preventparticles of solvent from getting on the hands, arms or even face of theperson operating the atomizer and serious dermatitis conditions result.

It is an object of this invention to provide novel compositions ofmatter containing hydroxy benzenes or homologues thereof which aresubstantially non-irritating to human epidermis.

It is a further object.of this invention to provide compositions ofmatter containing hydroxy benzenes or homologues thereof which do notcause dermatitis when contacted with human epidermis and which areuseful for removing carbon and gum deposits from internal combustionengines.

Other objects and advantages will be apparent from the followingdescription.

It has now been found that the escharotic action of certain hydroxybenzenes including homologues thereof, such as phenol, cresol, xylenoland carvacrol may be substantially, if not completely, inhibited bysimply mixing with one or more of the foregoing materials, a suitableproportion of one or more miscible esters of aromatic acids,particularly alkyl esters of aromatic dicarboxylic acids. Suitableesters include benzyl benzoate, dibutyl phthalate, dimethyl phthalateand amyl phthalate.

The amount of such esters which is required to eliminate the escharoticaction of the hydroxy benzene compounds varies widely depending upon theparticular hydroxy benzene ring compounds employed and the specificester or esters used therewith. For example, it is well known that theescharotic action of phenol and cresol is greater than that of most ofthe other hydroxy benzene ring compounds and it is apparent thereforethat a smaller amount of ester would be required to eliminate theescharotic action of the latter compounds than would be required in thecases of phenol and cresol.

In order to determine the amount of ester required to bring about thedesired results, a very simple test may be employed. A few drops of thecomposition to be tested are placed on the skin on the inner side of thewrist and allowed to remain there for about three minutes. If at the endof this time no burning or irritating sensation is noted, thecomposition may be said to have substantially no escharotic action.

The escharotic action of cresol so far as is known is one of the mostvigorous of any of the hydroxy benzene ring compounds, yet it has'beenfound that when compositions are prepared containing 67% by volume ofcommercial cresol and 33% of dibutyl phthalate, such compositions havesubstantially no escharotic action. Similar results are obtained withcompositions containing 50% by volume of cresol and 50% benzyl benzoate.

The effectiveness of such compounds as gum solvents was demonstrated bythe following method: Samples of gum obtained by exposure of crackedgasoline stocks to oxygen under elevated temperature and pressure weredissolved in acetone and sprayed on heated strips of shim stock. 0nstriking the heated metal, the volatile solvent evaporated leaving asmooth varnishlike deposit. The amount of gum thus deposited, preferablyabout 1.5 to 2 grams, was determined by weighing the shim stock-beforeand after the deposition. After coating with gum, the shim stock wasinserted as a sleeve in a chamber, the temperature and pressure of whichwas controlled to simulate conditions in the intake manifold of standardinternal combustion engines, namely, about 200 F. and a vacuum of about16" of Hg 1000 cc. of a by volume solution of the solvent under testdissolved in a regular grade gasoline was supplied thereto in anatomized state through a standard Carter carburetor. The solvent wasdissolved in gasoline in order to diminish the solvent power to a pointwhere all of the gum on the shim stock would not be removed under theforegoing test conditions. The shim stock was weighed after the solventtreatment and the loss in weight of gum deposit divided by the amount ofgum deposit originally present multiplied by 100 gave the percent gumremoval. sisting of 50% by volume of a commercial cresol When employing8. 00111130511108. 6011-,

(a mixture of about 35% ortho, 40% meta and para cresols and containingsmall amounts of phenol and xylenols) and 50% dibutyl phthalate in theforegoing procedure, 84% of the gum deposit on the shim stock wasremoved.

It is apparent that many combinations of hy droxy benzenes and estersmay be employed and that widely varying proportions of materials can beused. However, in general, superior results have been obtained whenusing compositions containing about 33% to 50% of dibutyl phthalate orbenzyl benzoate and 67% to 50% of phenol or cresol. This ratio oi!hydroxy benzene ring compounds and esters is preferably maintained whensuch compounds are used in coniunction with one or more additionalmaterials.

The invention is not limited to the foregoing specific compositionswhich are given by way of example only but is to be limited only by thefollowing claims.

We claim:

1. A composition comprising a hydroxy benzene ring compound havingescharotic action on the skin in such quantity as to impart to saidcomposition escharotic action in the absence of an agent to counteractsuch action, and an 5. A composition in accordance with claim 1.

where the ester is a lower alkyl ester of phthalic acid.

6. A composition in accordance with claim 1 where the ester is dibutylphthalate. 7. A composition in accordance with claim 1 where the esteris dibutyl phthalate and the amount of dibutyl phthalate is betweenapproximately and by volume of the hydroxy benzenes.

8. A composition in accordance with claim 1 in which the hydroxy benzenering compound is cresol, the aromatic acid ester is benzyl benzoate andthe cresol and benzyl benzoate are present in a ratio or from 6'1 to 50parts by volume of cresol to from 33 to 50 parts by volume of benzylbenzoate.

9. A composition of matter having non-escharotic action on the skincomprising approximately 67% by volume of cresol and 33% dibutylphthalate.

10. A composition of matter having non-escharotic action on the skincomprising approximately 50% by volume of cresol and 50% benzylbenzoate.

11. A solvent for removing carbonaceous deposits from internalcombustion engines comprising cresol in such quantity as to impart tothe solvent escharotic action on the skin and dibutyl phthalate in whichthe ratio of cresol to dibutyl phthalate is 67 to 50 parts by volume ofthe former to from 33 to 50 parts by volume 45 of the latter.

